The present disclosure is directed to fabrication of optical devices. More particularly, the disclosure provides methods and devices using a miscut (Al,Ga,In)N bulk crystal. Certain embodiments provided by the disclosure include techniques for fabricating light emitting devices using miscut gallium nitride containing materials. Such devices can be applied to applications such as optoelectronic devices. In certain embodiments, the disclosure provides methods of manufacture using an epitaxial gallium containing crystal with extremely smooth surface morphology and uniform wavelength over a large surface area of the substrate. Such crystals and materials include GaN, AlN, InN, InGaN, AlGaN, and AlInGaN, for manufacture of bulk or patterned substrates.
In the late 1800's, Thomas Edison invented the light bulb. The conventional light bulb, commonly called the “Edison bulb,” has been used for over one hundred years. The conventional light bulb uses a tungsten filament enclosed in a glass bulb sealed in a base, which is screwed into a socket. The socket is coupled to an AC power or DC power source. The conventional light bulb can be found commonly in houses, buildings, and outdoors. Unfortunately, the conventional light bulb dissipates more than 90% of the energy used as thermal energy. Additionally, the light bulb eventually fails due to evaporation of the tungsten filament.
Fluorescent lighting uses an optically clear tube filled with a noble gas, and typically also contains mercury. A pair of electrodes is coupled to an alternating power source through a ballast. Once the mercury has been excited, it discharges to emit UV light. Typically, the tube is coated with phosphors, which are excited by the UV light to provide white light. Recently, fluorescent lighting has been fitted onto a base structure to couple into a standard socket.
Solid state lighting relies upon semiconductor materials to produce light emitting diodes, commonly called LEDs. At first, red LEDs were demonstrated and introduced into commerce. Modern, red LEDs use aluminum indium gallium phosphide or AlInGaP semiconductor materials. Most recently, Shuji Nakamura pioneered the use of InGaN materials to produce LEDs emitting light in the blue range for blue LEDs. Blue LEDs led to innovations in lighting, and the blue laser diode enabled DVD players, and other developments. Blue, violet, or ultraviolet-emitting devices based on InGaN are used in conjunction with phosphors to provide white LEDs.